211 



Pleurotoma continued. 



nodulosa. . ovate-fusiform ; spire pyramidal, with nine rows of 



short nodulous ribs. . f inch. 



rentricosa. . ovato-fusiform, ventricose and caudated. . | inch. 

 terebralis. . fusiform, with transverse granulated striae and 



dentated keels. . inch. 



yramdata. . subturreted, granulated, base short. . \ inch. 

 brflexa. . subturreted ; spire long, plaits separate in their middle, 



a granulated keel. . small. 

 turrella. . subturreted ; the whirls carinated ; spire tubercu- 



lated in the upper part. . small. 

 striarella. . fusiform, turreted, ahnost smooth, plaits and striae 



hardly discoverable. . small. 

 decnssata. . fusiform, turreted; spire small, long, and nodulous, 



with two rows of tubercles, one small the other large. . 



| inch. 



Cerithium. 



interruptum. . pyramidal ; transverse striae in rows, alternately 



large and small ; ribs bowed, last turn ventricose. . T| 



inch. 

 hexayonum. . with five or six longitudinal ribs ; last whirl tumid, 



with five or six spinous tubercles. . 2 inches. 

 serratum. . turreted, echinated; two rows of compressed teeth 



on each turn, the lower smallest ; four internal plaits on 



right side. . 2f inches. 

 tricarinatus. . pyramidate ; three denticulated keels, the lowest 



by much the largest 2 inches. 

 i-ittatitm. . turreted ; upper whirls smooth, lower ones with 



three tuberculated bands 2 inches. 

 clavatulatum. . rough, with transverse tubercular keels, three 



at the upper part, and decreasing to one on the lowest 



turn; notched like a. pleurotoma 1 inch. 

 echinoides. . rather heptagonal, with tubercles a little pointed, 



in two or three rows ; twelve or fourteen turns, sometimes 



orange coloured ! inch. 

 a/igulosum. . pyramidate, twelve turns, with transverse striae, 



and a central angulated keel, points at the angles lj 



inch, 

 cristatum. . turreted ; whirls with a dentated keel in the middle ; 



the base transversely sulcated \\ inch. 

 calcitrapoides. . turreted, with transverse muricated ribs, no 



striae 1^ inch. 

 denticulatum. . spire subulated and smooth at the top, the other 



whirls denticulated with points in their upper parts, and 



striated beneath f inch. 

 umbrellatum. . the upper margins of the whirls denticulated, 



the under ones crenulated and expanded in the teeth of the 



next whirl, no striae, top of the spire smooth \~ inch. 

 larnellosttm. . turreted, subplicated ; distant transverse striae, 



base with three transverse lamellae 1^ inch. 



